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/**
 * @test
 * @bug 6869327
 * @summary Test that C2 flag UseCountedLoopSafepoints ensures a safepoint is kept in a CountedLoop
 * @library /test/lib /
 * @requires vm.compMode != "Xint" & vm.flavor == "server" & (vm.opt.TieredStopAtLevel == null | vm.opt.TieredStopAtLevel == 4) & vm.debug == true
 * @requires !vm.emulatedClient & !vm.graal.enabled
 * @modules java.base/jdk.internal.misc
 * @build jdk.test.whitebox.WhiteBox
 * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
 * @run driver compiler.loopopts.UseCountedLoopSafepointsTest
 */

package compiler.loopopts;

import jdk.test.lib.Platform;
import jdk.test.lib.process.ProcessTools;
import jdk.test.lib.process.OutputAnalyzer;
import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import jdk.test.lib.Asserts;

/* Idea of this test is to check if ideal graph has CountedLoopEnd->SafePoint edge in case
   of UseCountedLoopSafepoint enabled and has no such edge in case it's disabled. Restricting
   compilation to testMethod only will leave only one counted loop (the one in testedMethod) */
public class UseCountedLoopSafepointsTest {

    public static void main (String args[]) {
        check(true); // check ideal graph with UseCountedLoopSafepoint enabled
        check(false); // ... and disabled
    }

    private static void check(boolean enabled) {
        OutputAnalyzer oa;
        try {
            oa = ProcessTools.executeTestJava(
                    "-XX:+UnlockDiagnosticVMOptions", "-Xbootclasspath/a:.",
                    "-XX:" + (enabled ? "+" : "-") + "UseCountedLoopSafepoints",
                    "-XX:+WhiteBoxAPI",
                    "-XX:-Inline", "-Xbatch", "-XX:+PrintIdeal", "-XX:LoopUnrollLimit=0",
                    "-XX:CompileOnly=" + UseCountedLoopSafepoints.class.getName() + "::testMethod",
                    UseCountedLoopSafepoints.class.getName());
        } catch (Exception e) {
            throw new Error("Exception launching child for case enabled=" + enabled + " : " + e, e);
        }
        oa.shouldHaveExitValue(0);
        // parse output in seach of SafePoint and CountedLoopEnd nodes
        List<Node> safePoints = new ArrayList<>();
        List<Node> loopEnds = new ArrayList<>();
        for (String line : oa.getOutput().split("\\n")) {
            int separatorIndex = line.indexOf("  ===");
            if (separatorIndex > -1) {
                String header = line.substring(0, separatorIndex);
                if (header.endsWith("SafePoint")) {
                    safePoints.add(new Node("SafePoint", line));
                } else if (header.endsWith("CountedLoopEnd")) {
                    loopEnds.add(new Node("CountedLoopEnd", line));
                }
            }
        }
        // now, find CountedLoopEnd -> SafePoint edge
        boolean found = false;
        for (Node loopEnd : loopEnds) {
            found |= loopEnd.to.stream()
                                 .filter(id -> nodeListHasElementWithId(safePoints, id))
                                 .findAny()
                                 .isPresent();
        }
        Asserts.assertEQ(enabled, found, "Safepoint " + (found ? "" : "not ") + "found");
    }

    private static boolean nodeListHasElementWithId(List<Node> list, int id) {
        return list.stream()
                   .filter(node -> node.id == id)
                   .findAny()
                   .isPresent();
    }

    private static class Node {
        public final int id;
        public final List<Integer> from;
        public final List<Integer> to;

        public Node(String name, String str) {
            List<Integer> tmpFrom = new ArrayList<>();
            List<Integer> tmpTo = new ArrayList<>();
            // parse string like: " $id    $name       ===  $to1 $to2 ...   [[ $from1 $from2 ... ]] $anything"
            // example:  318    SafePoint  ===  317  1  304  1  1  10  308  [[ 97  74 ]]  ...
            id = Integer.parseInt(str.substring(1, str.indexOf(name)).trim());
            Arrays.stream(str.substring(str.indexOf("===") + 4, str.indexOf("[[")).trim().split("\\s+"))
                  .map(Integer::parseInt)
                  .forEach(tmpTo::add);
            Arrays.stream(str.substring(str.indexOf("[[") + 3, str.indexOf("]]")).trim().split("\\s+"))
                  .map(Integer::parseInt)
                  .forEach(tmpFrom::add);
            this.from = Collections.unmodifiableList(tmpFrom);
            this.to = Collections.unmodifiableList(tmpTo);
        }
    }
}